. Nitric Oxide (NO) donor compounds have been shown to be effective in decreasing platelet adhesion to polymer surfaces. Until recently, the donor compounds were mixed with polymers and used as a coating, and NO was released at the blood/plastic interface. Leaching of undesirable by-products of the NO release reaction resulted in efforts to covalently bond NO donors directly to the polymer backbone. Preliminary studies with such NO releasing polymers have shown remarkable success. In Phase II of this research, several common polymers will be modified by the addition of NO donor groups, using proven synthesis techniques. The resulting polymers will be extruded into tubing, which will be tested in vitro and in an in vivo model of extracorporeal circulation to investigate mechanical, chemical, and biocompatibility properties of the materials. Manufacturing, processing, and storage of these NO release polymers will be investigated. The aim of this research is to determine a practical and effective means of employing NO releasing polymers in fabrication or coating of blood contact devices. PROPOSED COMMERCIAL APPLICATION: The nitric oxide-releasing polymers developed in this project will have potential commercial applications in improving biocompatibility of blood-contract surfaces. Examples include the manufacture and/or coating of tubing and blood contact devices used in heart/lung mechanes and hemodialysis. These compounds may also be used in implanted devices or for localized nitric oxide delivery.